Hub nodes are essential nodes in optical networks carrying data traffic comprising data information on a number of optical wavelength channels in optical fibres. The hub node connects uplink traffic from one or more network nodes to a higher-tiered network. The edge node then performs subscriber management and routes the uplink traffic, typically at the packet level, towards an appropriate destination, such as to content services, back towards the access networks, to the Internet, etc. Such edge node routing may entail sending the uplink traffic to a regional network, which operates back at the optical layer. Thus, a hub node connects to multiple edge nodes and the edge nodes in turn connect to the regional network.
For an optical layer centric solution, transport convergence is essential, i.e. such transport network should be capable of transporting any type of service. Such services include mobile backhaul, either traditional Ethernet/packet based or main-remote based with, e.g. Common Public Radio Interface (CPRI), business services, and residential services. Some networks comprises in accordance with their defined functionality and configuration two transport interfaces: one at the access location and one at the service edge.
The service edge location can also be called a Hub to put emphasis on the typically more or less hubbed traffic profile or access/aggregation networks. At the service edge, the different services may be represented by different equipments/physical ports.
The physical ports at the Hub are typically fixed in wavelength. A hub arrangement comprises at least one Wavelength Selective Switch, WSS, for directing the wavelength channels and the data packets carried by the wavelength channels to different services, and for directing wavelength channels from the service equipment to a Central Office (CO) node. The WSS is connected to one or more COs. Such architecture has a number of problems and drawbacks, e.g.                Underutilization as ports may not be needed for those particular connected COs or may be of the wrong wavelength for the service provided by the port;        Lack of ports for a particular service.        